Telegraph repeating system



July 18, 1933. F. 5 KINKEAD 18,900

TELEGRAPH REPEATING' SYSTEM Original Filed July 14, 1928 LOOP 14577 d LOOP EAST k Q I I k 9 k a 5. g t 4.1 g T k 3 lo +Q k i q lNl/ENTOR FSK/NKEAD.

ATTORNEY Rama July 18, 1933 UNITED STATES PATENT OFFICE FULLERTON s. xINKEAnor BROOKLYN, New YORK, ASSIGNOR To BELL TELEPHONE LABORATORIES, INCORPORATED, OF NEW YORK,

YORK

Original No. 1,752,436, dated April 1 1930, Serial No.

filed July 16, 1931.

This invention relates to telegraph systems and particularly to repeaters for repeating telegraph signals from one closed, non-polar telegraph circuit to another.

An object of the invention is to reduce the installation and maintenance expense of a telegraph repeating system by reducing the number of sources of'power required.

A feature of the invention is a repeater system adapted to repeat signals from either of two connected line sections into the other, and utilizing polar relays operated from a single grounded battery of either polarity.

It was long the practice in designing repeaters for single line telegraph systems to utilize neutral or non-polarized relays or combinations of such relays with other nonpolarized instruments. Non-polarized relays are less eflicient than polarized relays, being 1 more sluggish in their action and requiring more current to operate, and. accordiinglv. repeaters utilizing polar relays were developed and adopted. A repeating system of the latter type isdisclosed in patent to J. M. Fell 1479,430 Januarv .1. 1914. Such systems operate satisfactorily but require for their op eration two sources of current of opposite polarities with respect to ground. In practice this is usually supplied from two batteries connected in series with the mid-connection grounded.

In accordance with this invention a repeater circuit is provided which utilizes polar relays but requiresfor its operation only a single grounded source of current of either positive or negative polarity. The effect of a second source of current of opposite polarity is produced by means otpotentiometer arrangements of resistances.

Fig. 1 if'the drawing contains a! diagram showing a simplified circuit of a repeater in accordance with this invention, and

Fig. 2 shows the .same circuit diagram drawn in amanner to show that the circuit embodies a double Wheatstone bridge arrangement, wherein a relay connected across the bridge points of each bridge controls I a leg of the other bridge.

The following-description applies equally we1lt0each-figure:- I

TELEGRAPH REPEATING SYSTEM.

292,701, filed July 14, 1928. Application for reissue Serial No. 551,269. I i

-The repeater comprises, referring to the drawing, four polar relays properly associated with a single sourceofgrounded potential 1, and resistors 2 to 7.

The relays are arranged in pairs,one pair comprising a line rela west LRW, and an auxiliary relay west A W, having theirupper,-'or line, windings connected in series with the loop west circuit and the other pair comprisinga-line relay east LRE, and an auxiliary "relay east ARE, having their upper windings connected in series with the loop east circuit. The loop west circuit also includes the contacts of the opposite line relay LRE and theloop east circuit includes the contacts of the opposite line relay LBW.

For purposes of explanation let it be assumed that an electron flow through any winding of any relay, as they are shown in the drawing, tends to urge the relay tongueto make contact upon the side toward'which the electron flow is.proceeding.- For instance, when no signals are being repeated the loop west is closed through a source of current,,at the distant station, of such polarity as to N. Y., A CORPORATION OF NEW cause an electron flow from left, to right through the upper windings of relays LBW and ARW and hold the tongues of those relays against their contacts. At the same time the loop east is closed through a source of current, at the eastern station, of such polarity as to cause an electron flow from right to left through the upperwindings of relays LBE and ARE and hold the tongues of those relays against their contacts.

When no signals are being repeated, the relay tongues are in the positions shown in the drawing, and a local circuit is completed from the negative terminal of the battery 1, through the contacts on relay ARE and resistor 6 to the positive terminal of the battery. Resistor 6 has an impedance large as coinpared with that of the path from the negative terminal of the battery through the relay contacts and, therefore, point 12 is at substantially the potential of the negative terminal of battery 1. Now th ere is a pathin-parallel.

to the one just outlined through resistors 33 and 2.

These resistors have substantially equal impedances, and therefore the voltage contacts of relay ARW and resistor 7 which.

across each is about; half the voltage of battery 1. Hence pointlO is positive with respect to point 12 and there is aresultant elec- I tron flow from right to left through the lower or biasing windings of relays ,LRVV and ARW." This biasing currenttends to move the relay tongues to the'left, but its efl'ect is overcome by the stronger line current flowing windings of the relay.

There is also a flow ofcurrent through the in the 'o ppositedirection through the upper.

maintains point13negative with respect to point 11 and Causes an electron flow from left to right through the biasing windings of relays ARE and LRE. This current, how'- ever, is weaker than the line current flowing in the opposite direction through the upper windings, and the relay tongues are held against their, contacts by the stronger line current. 1 l

' When telegraph signals are transmitted from loop West to loop east, the loop west'is opened, breaking the normal flow of line current through theupper windings of relays LRVV andi-LRTV. These relays thereupon move their tongues tothe left in response to the biasing current in their lower windings.-

Relay LRWV repeats the open signal to the loop east by opening the lattercircuitat the relay contacts.

. This opening of the loop east at the contacts of relay LRW breaks the normal flow of line current through the line windings o'fre 'lays ARE and LRE, but the'tongues ofthose relays remain against their contacts because the d1rect10n of the normal "biasing current through their lower windings was reversed when relay ARWoperated and opened the circuit from the negative terminal of battery 1 to Point 13. Thus, with the contacts of relay ARW open, resistor? and the lower wind- 'ings of relays ARE and LREare connected in T battery 1.

seriesacross resistor 4, Hence electrons .flow from the negative terminal of battery 1 through resistor 5, from right to left through the lower windings of relays ARE and LRE, throughresistor-7,.to the positive terminal of hen the loop west isiopen in the course of sending an open impulse from west to east the contact 0 f. relay ARlV is open. While this open condition persists, opening of the loop east cannot reverse the position of the armature-of relay LRE because opening of the contacts of relay ARW conditionsthe bridge circuit in which the relay LRE has its winding to hold the relay LRE with its contact close-d. Since signal impulses consist of open condltlons transmitted from oneline to.

, the other this arrangement prevents reflecnormal line current overcomes thebiasing tion of sigial impulses. transmitted from one line back into that line. Q

When the loop west is again closed; the

current in the windings of relays LBW and Ali-WV and moves the tongues of those relays to the right restoring the; circuit to its original condition and repeating a closed impulse into the loop east, v

When signals are transmitted from east to west the operation of the repeater is the con verse of that outlined, relay. LRE operating to openthe loop west and relay operating to reverse the direction of the biasing current inrelays LRVV and ARW so that they will not operate when their line windings are opened at relay LRE.

Should the operator at one line terminal transmits break signal while the operator at the distant terminal is transmittlng', the

break signal-will be transmitted through the repeater in the "following manner. 1

Assume'that' signals are being transm tted from loop west to loop east and the operator at the eastern station breaks the loop east. If

an opensignal is being trasmitted' trom loop west at that instant there will beno change in the positions of the relays at the repeater,

but as soon thereafter as loop westis closed, the tongues of relays LR-Wand ARW'nrove to the position shown in the drawing. This closes the normal biasing circuit: through they contacts of relay ARWV- and the lower W1nd ings of relays ARE and LRE,'mo ving the tongues of those rel'aysaway from their con it is desirable to have the biasing current that is claimed is: 1. A telegraph repeater'fo'rrepeatrngbe about half as stron sxth-e'linecurrent.

tween two closed, non-polar telegraph-circuits each conta ning a source of current, comprising a first anda second polar relay means each having a first and a second independent actuating winding and a first and a second pair of contactsg the firstwinding of said first means being connected through the first set of contacts on said second means to one line, section and the first :w ndmgs ofsaid second 'means being connected through theiirstset v of contacts on said first :means to" the other line section, means comprising a single source of electromotive force of constant polarity,

a first resistor, "and the second pair=ot contaets on one of said relaymeans, for supplying'a current'to the: second winding on the other relay means opposite in effect to; the normal line current inthefirstjwinding of said other relay'mea'ns, and means compris- Iingsaid source of; electromotive force, a. second-andathirdresistor for suplying'a curing two line sections, a pair of relays connected-with each section, each relay having gin-armature and two w ndings, each-of said windings being serially connected toa corre- -sponding winding. of the otherrone of the same pair, adine circuit for each section normally closedthrough one winding of each relay. of one pair and contacts of a relay of the 1 other pair, two local circuits one for the other.

windings of-each pair, a single'source of elec- "tromotive force and resistance elements, one of saidlocal clrcuitsextending from one ter- -m1nal of said source 'through'one of said resistanceelements', said other windings of'one pair, and a second resistance, to the other terrninal ofsaid source, and the other local circuit extending from said ,one terminal ithrough the contactsofthe other relay of said other pair of relays through said other windings in opposite sense to said first local circuit,

throu-gha third resistance, to the other terminalot said source.-

I 3. A telegraph repeater system "comprising two line sections, relay means for each secition, each relay means having a line'wind- 111g; an allXlllitlYWVllldlIlg and a set of contacts, the line winding or each relay means :being connected. to the corresponding line SCCUOH through the set of contacts on the other relay means, instiannentalities for supplying a current in onedirectio'n through the auxiliary winding of one relay means, said in'strum-entalities comprising a source of elcctrorn'otlve torce, a potentiometer bridged;

acrosssaid source, one auxiliary winding terminal'being connected to" an intermediate point on said potentiometer, the other winding terminal being connected through a resistance to one terminal of the source, and

means for reversing the flow of the auxiliaryv winding current comprising a second set of contacts on the other relay means for connecting the other auxiliary winding terminal directly or through a lower resistance to I g tion, a second line section, a first Wheatstone bridge for repeating impulses from the other of said line sections into the first line section, and means controlled by said bridges for preventing the reflection of signals received over said line sections back therein.

5. In a telegraph repeater, a first line sec-. tion, a second line section, a first and second Wheatstone bridge, and means whereby each of said bridges controls a {legofthe-othe'r of said bridges.

lay'means in each of said line sectionsadapted to control the leg of its associated bridge. 1

7. In a telegraph repeater, a first line se,c.

tion, a'second. line section, a Wheatstone bridgefor each of said line sections, each, of

said bridges including a relay for controlling a leg of the other of said bridges.

8. :In a telegraph repeater, a first linesection, a second line section, a Wheatstone bridge forea'ch of said line sections, a relay connected between the bridge points of each bridge, the relay ofeach bridge controlling a leg ofthe other bridge.

9.. In a telegraph repeater, a first-line section, a second line section, a first Wheatstone bridge associated with said first linesection, a second Wheatstone bridge associatedwithsaid second line section,'a relay connectedbetweenthe bridge points of said first bridge,

said relay controlling a leg of said second bridge, means responsive to impulses transmitted over said first line section for controlling said relay, arelay connected between the bridge points of said second bridge, said lastmentioned relay controlling a leg of said-first bridge, and means responsiveto impulses transmltted over said second line section for controlling sald last-mentioned relay.

10. In a telegraph system, a first line section, a second line section, a first Wheatstone .bri'dge associated with'said-first line section,

a second "Wheatstone bridge associated with said second line-section, a relayconnected between the bridge points of-"said first bridge, said relay controlling saidjsecond line'section, means responsive to impulses transmitted over said first line section for controlling said relay, a relay connected between the bridge points of said second bridge, said last-mentioned relay controlling said first line section, and means responsiveto impulses transmitted over said second line section for controlling said last-mentioned relay.

11. In a telegraph repeater, a first line seebridge associated with said first line section, a second Wheatstone bridge associated with I said second line section, a pair of relays connected between the bridge points of said firstlays controlling one leg of said first bridge,

i and means responsive to 'im'pulse's transmittedoversaid second line section fo'r 0011- trollin said last-mentioned relays.

12'. n a telegraph repeater, a first'line section, a second line section, a firstWheatstone bridge associated with said first line section,

a second Wheatstone bridge associated with said second line section, a pair of relays con- I n'ected between the bridgepointsiof said first I bridge, said relays being connected in series with each other, one of said relays controlling the second line section, the otherjof said relays controlling one leg of said second bridge, means" responsive to impulses transmitted over said first line sectionfor controlling said relays, a pair of relays connected between the bridge points of said second bridge, said lastmentioned relays being connected in series with each other, one of said last-ment oned relays controlling the first line section, the

other of said last-mentioned relays control- I ling one'leg of said first bridge, and means mentioned relays.

responsive to. impulses transmitted over said second line section for controlling said last- 13. In a telegraph repeater, two Wheatstone bridges, eachof said bridges comprising three legs of equal resistance "and one leg Y of lower resistance, means for controlling the low resistance leg of each-bridge whereby the difie'rence of potential between: thebridge points thereof is varied, anelectromagnetic leg'of the second bridge, and the electroma g- V ne tic means ofthe second bridge controlling means connected across the bridge points of each bridge, the'electromagnetic means of the first bridge controlling the low resistance the low resistance leg of the first bridge.

' 14. Ail electric circuit network comprising bridge circuit, hug the balance of said bridge circuit, and 3 means responsive to reversal of balance in 1 force and to saidrelay, and a plurality of resistances connected tosaid relay, source and versal of current from said source through said relay.

contact, and a path from said source through said contact when closed whereby operation L ,of said-make and break contact causes re- 15. In a telegraph repeater, two polar re} ceiving relays,

comprising each an unbalancedWheatstone iasing circuits for each may, I.

bridge circuit, each receiving relay operative r to reverse the'balance-of the bridge circuit 1 of the other relay, each relay 'bei'ng'inoperative when its own bridge circuitjis reversed in balance. I v

16. In a telegraph system, a first line circuit, a second line circuit, polar receiving relays, one for each circuit, biasing windings one for each relay, means whereby the operation bybnehne circuit of-either receiving relay opens the other line circuit and reverses the bias of the other receiving relay, said means comprisingin part unbalanced'wheat stone bridge circuits,each bridge controlled by 'one'of said receiving relays and containingthebiasing winding of th other receiving relay. r

. 17. In a telegraph repeater, a Wheat-stone i a receiving relay for controlsaid bridge circuitifor preventing reflection signals in the repeater. a 1

- 18. In a telegraph repeat-er, two receiving relays and two Wh'eatstone bridge circuits each controlled by one of said relays to ram vder the remaining one of said relays inefl:'ec-' .tive, a line circuit including a winding of one of said relays, and a line circuit includ- Ying'a winding of'the other of said relays,

said line circuits and said' repeater constituting a two-way channel for'the transmission of telegraph impulses.. i FULLERTON ;S. KINKEAD. 

